# Revision history [back]

### Vertex connecitivity incomplete (pun intended)

I am no graph theory expert, but the textbook I am learning from, and the Wikipedia article "Connecitivy (graph theory)" (which doesn't use my book as a reference, i.e., there are at least 2 books saying this) both say the vertex connectivity of a complete graph on n vertices is n-1. But, if you try to do graphs.CompleteGraph(whatever).vertex_connectivity(), it says

"There can be no vertex cut in a complete graph."

So, how do we fix this? I know nothing.

### Vertex connecitivity incomplete (pun intended)

I am no graph theory expert, but the textbook I am learning from, and the Wikipedia article "Connecitivy (graph theory)" (which doesn't use my book as a reference, i.e., there are at least 2 books saying this) both say the vertex connectivity of a complete graph on n vertices is n-1. But, if you try to do graphs.CompleteGraph(whatever).vertex_connectivity(), it says

"There can be no vertex cut in a complete graph."

So, I looked at the code, and the fix is simple: Take

if g.is_clique():
raise ValueError("There can be no vertex cut in a complete graph.")


and make it

if g.is_clique():
return g.order()-1


But, I don't know how do we fix this? I know nothing.this fixing stuff works.

Second question, why does it return answers in the form 1.0 when the only possible values of this are integers?

### Vertex connecitivity incomplete (pun intended)

I am no graph theory expert, but the textbook I am learning from, and the Wikipedia article "Connecitivy (graph theory)" (which doesn't use my book as a reference, i.e., there are at least 2 books saying this) both say the vertex connectivity of a complete graph on n vertices is n-1. But, if you try to do graphs.CompleteGraph(whatever).vertex_connectivity(), it says

"There can be no vertex cut in a complete graph."

I looked at the code, and the fix is simple: Take

if g.is_clique():
raise ValueError("There can be no vertex cut in a complete graph.")


and make it

if g.is_clique():
return g.order()-1


But, I don't know how this fixing stuff works.

Second question, why does it return answers in the form 1.0 when the only possible values of this are integers?

Thirdly, there are a couple typos in the commenting of the code:

In a grid, the vertex connectivity is equal to the minimum degree, in which case one of the two sets it of cardinality 1::

should be "two sets IS of"

For directed graphs, the strong connexity is tested through the dedicated function::

I believe should be "strong vertex connectivity". Maybe connexity is okay but I am guessing it's a typo.

### Vertex connecitivity incomplete (pun intended)

I am no graph theory expert, but the textbook I am learning from, and the Wikipedia article "Connecitivy (graph theory)" (which doesn't use my book as a reference, i.e., there are at least 2 books saying this) both say the vertex connectivity of a complete graph on n vertices is n-1. But, if you try to do graphs.CompleteGraph(whatever).vertex_connectivity(), it says

"There can be no vertex cut in a complete graph."

I looked at the code, and the fix is simple: Take

if g.is_clique():
raise ValueError("There can be no vertex cut in a complete graph.")


and make it

if g.is_clique():
return g.order()-1


But, I don't know how this fixing stuff works.

Second question, why does it return answers in the form 1.0 when the only possible values of this are integers?

Thirdly, there are a couple typos in the commenting of the code:

In a grid, the vertex connectivity is equal to the minimum degree, in which case one of the two sets it of cardinality 1::

should be "two sets IS of"

For directed graphs, the strong connexity is tested through the dedicated function::

I believe should be "strong vertex connectivity". Maybe connexity is okay but I am guessing it's a typo.

Fourthly, can we make "graph theory" a tag? 5 retagged

### Vertex connecitivity incomplete (pun intended)

I am no graph theory expert, but the textbook I am learning from, and the Wikipedia article "Connecitivy (graph theory)" (which doesn't use my book as a reference, i.e., there are at least 2 books saying this) both say the vertex connectivity of a complete graph on n vertices is n-1. But, if you try to do graphs.CompleteGraph(whatever).vertex_connectivity(), it says

"There can be no vertex cut in a complete graph."

I looked at the code, and the fix is simple: Take

if g.is_clique():
raise ValueError("There can be no vertex cut in a complete graph.")


and make it

if g.is_clique():
return g.order()-1


But, I don't know how this fixing stuff works.

Second question, why does it return answers in the form 1.0 when the only possible values of this are integers?

Thirdly, there are a couple typos in the commenting of the code:

In a grid, the vertex connectivity is equal to the minimum degree, in which case one of the two sets it of cardinality 1::

should be "two sets IS of"

For directed graphs, the strong connexity is tested through the dedicated function::

I believe should be "strong vertex connectivity". Maybe connexity is okay but I am guessing it's a typo.

Fourthly, can we make "graph theory" a tag?